Actually I've been noticing that many puzzles have one entry the same or similar to one from the day before. I believe AAH appeared yesterday and today, Tuesday. RICER appeared on successive days over the weekend. Hap? Only the editor knows for sure.

Words definitely seem to make the rounds more than mathematical coincidence might suggest. Or does it?

I love the fact that you only need 33 people in a room for any two to have the same birthday (not necessarily a particular birthday, but with crosswordese (Or as I like to call it crossrote) given the utility of certain words, it happens - it's the fact that it is the same words appearing in same day different source puzzles or in sequential puzzles that catches our attention. The Tuesday LAT had some fresh fill today, but I'll wait for that thread starter*.